WASHINGTON, DC - MAY 08: House Veterans Affairs Committee chairman Rep. Jeff Miller (R-FL) (R) talks to ranking member Rep. Michael Michaud (D-ME) during a committee business meeting May 8, 2014 on Capitol Hill in Washington, DC. The committee has voted to subpoena Veterans Affairs Secretary Eric Shinseki regarding allegations that up to 40 veterans may have died while waiting for medical treatment at a central Phoenix hospital and whether there was a secret list to hide the delay. (Photo by Alex Wong/Getty Images)

Veterans Affairs Secretary Eric Shinseki brushed aside calls for his resignation Thursday and got an unexpected political lifeline from House Speaker John Boehner following reports that 40 patients died because of delayed treatment at an agency hospital.

Meanwhile, other lawmakers voted Thursday to subpoena records relating to a waiting list for care at the Phoenix facility in a growing probe of veteran health care.

"I'm not ready to join the chorus of people calling on him to step down," Boehner, R-Ohio, said of Shinseki at a news conference, adding that there is a "systemic management issue throughout the VA that needs to be addressed."

The American Legion and some in Congress have called for Shinseki's ouster following allegations that patients died at the Phoenix VA hospital due to delays in care and that the hospital kept a secret list of patients waiting for appointments to hide the delays.

Shinseki, a retired Army general, told CBS that he sent inspectors to Phoenix immediately after he learned of reports about the deaths. "I take every one of these incidents and allegations seriously, and we're going to go and investigate," he said.

Hours later, the House Veterans Affairs Committee voted unanimously to subpoena all e-mails and other records in which Shinseki and other VA officials may have discussed destruction of what the committee called "an alternate or interim waitlist" for veterans seeking care at Phoenix.

Shinseki answered in a letter Wednesday that VA employees used "transitory or interim notes ... for reference purposes" as they were moving information to the new electronic waiting list system. Regulations of the National Archives and Records Administration require that such notes be destroyed when they are no longer needed for reference, the VA says.

Dissatisfied with that response, the committee subpoenaed all documents relating to the destruction and gave Shinseki until 9 a.m. May 19 to produce them. The VA said that it will review the subpoena and respond.

Shinseki announced last week that three officials at the Phoenix facility have been placed on leave while the VA inspector general investigates.